1. Field of the Invention
The present invention relates to an outboard motor including a transmission device arranged to change the speed or the direction of rotation of an engine and to transmit the rotation to a propeller.
2. Description of the Related Art
WO 2007-007707 A1 proposes an outboard motor including a hydraulic clutch type transmission mechanism that shifts the speed of rotation of an engine between high speed and low speed positions and transmits the rotation to a propeller, an oil pump for supplying hydraulic pressure to the hydraulic clutch type transmission mechanism, and a hydraulic pressure control valve for controlling hydraulic pressure supplied to the hydraulic clutch type transmission mechanism. A solenoid type hydraulic pressure control valve in which an electromagnetic coil is energized to open or close a valve body is generally applied to the hydraulic pressure control valve.
However, when the solenoid type hydraulic pressure control valve is applied, it is necessary to cool the valve at a position that depends on where the valve is located because the hydraulic pressure control valve generates heat. In this case, if the hydraulic pressure control valve is constructed to be cooled by a separate cooling mechanism, it results in a complicated construction and a cost increase.
Depending on how the hydraulic pressure control valve is arranged, there is concern that the outboard motor may increase in size and the distance from the center of gravity of the outboard motor to a hull may increase, thereby increasing an applied load on a clamp bracket supporting the outboard motor on the hull.